NFS-Ganesha is a user mode file server with support for both the
NFS suite and 9P, the Plan 9 remote file access protocol. It uses
an internal meta data cache and state manager for performance. It
also provides support for pNFS for multiple clustered file systems
both open source and proprietary. Multiple file systems are supported
via loadable back-end drivers. The VFS back-end supports file systems
via the kernel. Other back-ends can support user mode library based
clusters such as CEPH and GLUSTERFS. There is also a PROXY back-end
which operates as an NFSv4 client.